Generally, there are two main types of known dietary fibers broadly classified as soluble fibers and insoluble fibers. Insoluble fibers are recognized for their bulk laxative effect, while soluble fibers are known to have a cholesterol-lowering effect. Certain natural grains, particularly farinaceous grains, contain both soluble and insoluble fibers, and are particularly useful as fiber sources because they can be manufactured into a wide variety of edible products for consumption. Insoluble fibers are generally found in the husk of the grain, while soluble fibers may be found in the husk or in other parts of the grain. Examples of soluble fibers that have been shown to have a cholesterol-lowering effect include, e.g. psyllium and .beta.-glucan.
Psyllium an excellent source of both soluble and insoluble fibers, and has a proven cholesterol-lowering effect. Psyllium is known mucilaginous material derived from seeds from the plants of the Plantago genus, which grows in certain sub-tropical regions. The seeds are dark brown, smooth, boat shaped and shiny. In addition to its cholesterol lowering effects, psyllium is well known for its bulk laxative effect. Psyllium seed is used in whole, ground or dehusked form to make a variety of psyllium containing products, including cookies, laxative drink mixes, and other foodstuffs.
Psyllium is mucilagenous in nature and acquires a slimy or adhesive texture and mouthfeel upon hydration. This slimy mouthfeel is unpalatable and, accordingly, various additives have been incorporated in psyllium-containing ingestible compositions to mask the undesirable texture and mouthfeel of psyllium. In addition, psyllium develops a distinctive, undesirable flavor and color in the presence of heat and moisture which further limits its use in food and drink mix products.
The mucilagenous nature of psyllium husks and of soluble fibers in general presents grave processing difficulties and there have been numerous prior attempts to produce palatable, food and drink mix products. Difficulties notwithstanding, the desirable therapeutic effects provided by psyllium have led to many prior art psyllium-containing formulations. For example, various psyllium containing foodstuffs have been proposed which purport to take advantage of the natural digestion regulation properties of psyllium, or the satiating effect of psyllium. See, for example, U.S. Pat. Nos. 3,574,634 and 4,348,379.
It has also been suggested, e.g. in U.S. Pat. No. 3,148,114, that whole psyllium husks, such as the ground husks of the seed Plantago psyllium, lowers blood cholesterol upon oral administration thereof. U.S. Pat. No.4,849,222 discloses a medicament composition for reducing blood cholesterol levels in humans and lower animals which comprises a mixture of psyllium seed gum, or source of psyllium seed gum, and a nonabsorbable, nondigestible polyol polyester.
Prior attempts have been made to overcome the problems of using psyllium in ready-to-eat cereal and bakery products such as cookies. U.S. Pat. No. 5,227,248, hereby incorporated by reference, describes preparation of an extruded psyllium nugget that is incorporated into cereal and baked products such as cinnamon cookies. The nuggets used were approximately 1/8 to 1/4 inch in diameter.
The mucilagenous nature of psyllium and other soluble fibers provides particular difficulties in the preparation of psyllium-containing drink mix products. As noted above, psyllium gels when exposed to an aqueous environment, leading to palatability and stability problems such as poor suspendability. Attempts have been made to control the psyllium particle size, slow the gellation rate of psyllium in a liquid formulation by inclusion of, e.g. citric acid, and addition of suspending agents. Certain dry psyllium-containing formulations are commercially available, as liquid drink mixes have proven to have an inadequate shelf life for commercialization.
The present invention provides fiber-containing intermediates comprising a soluble fiber source and an insoluble fiber source that overcome the defeciencies associated with prior art products containing soluble fiber sources such as psyllium. The extruded intermediates are useful in preparing palatable foodstuffs, e.g. drink mix and baked good formulations. Methods of producing the intermediates are also described herein. The food and drink mix preparations, and even the intermediates themselves, are useful for reducing serum cholesterol levels upon administration to a mammal, e.g. a human. Additional objects and advantages of the present invention will become apparent from the following detailed description and examples thereof.